From patchwork Fri Jan 25 00:10:14 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiong Wang X-Patchwork-Id: 1030734 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=netronome.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=netronome-com.20150623.gappssmtp.com header.i=@netronome-com.20150623.gappssmtp.com header.b="ssdxaUU6"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43lzwS5NDSz9s55 for ; Fri, 25 Jan 2019 11:11:52 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728053AbfAYALv (ORCPT ); Thu, 24 Jan 2019 19:11:51 -0500 Received: from mail-wm1-f68.google.com ([209.85.128.68]:40169 "EHLO mail-wm1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727665AbfAYALu (ORCPT ); Thu, 24 Jan 2019 19:11:50 -0500 Received: by mail-wm1-f68.google.com with SMTP id f188so4923258wmf.5 for ; Thu, 24 Jan 2019 16:11:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netronome-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=EJQP/vrZDdzlT17Gt5cjzNj8GSxGKxcs+GqQGramIAs=; b=ssdxaUU6FkabBZoVVCORRdMdhWwNeLvmW4Zy6SC/L+UNL1249iFgzEqZPUALtdZgfM 79v0w89uZIETdmBKMmwG8zCS8MCWmvIFeefVBhwcirmCkfQx6iC9DIIOIp7cPrrVMKeS MYAymODgPGPzRY5B7U3YumVIZ/DyLLfiVue6ZoS3bmCxgtPfcSGQiFKnw1CJwwQtVg3O ECQBbFp90wgKbbZbPD5pWf/4Vlyv6JLpIQdmuSM2XMHrXpNIbmH+1a5kaWnuyjADS5pF mURkObufXDyZLykiszgirFDssOAAwnHeVYpe51lG04JeWTjTCR18pMoE3pRzar0rkBLz QoYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=EJQP/vrZDdzlT17Gt5cjzNj8GSxGKxcs+GqQGramIAs=; b=Kh22J6wa3GTDaFRzndhAUV1xgeVAQa16858LwV0Z70y8R3UtEERI6h50V3mPcmaZny yyG4rEKPArsOH81UGYr43ZccIlq5eTUXg/K8fD18OaVQsIfNn1Lygy1f2bIG+jEArnKS 7h0mAHjDD9OoWeBIZx4mpK4yfSfty0Ypmu5XIWOXPokSk6fHtw1zpZW3RqDfUafguuI/ 1iOcZLuUAByrcYNnG0P8ID2jVxv2/8c8RyT0aZgGgzj3NU26d6WyORLeLRJbF409mm5Z 4aC5A6uGxMCjRjC969FnNEhy1gyQtGNrOiittkp2ACX0NStRSgrOkvJI4FSUyi/H0g62 Cf+A== X-Gm-Message-State: AJcUukeI2GeJFMPwhiPNlCVSawhHQcVujHKEU+6vHWy/kUIxyQ7VlUMi UbopfGDcL++4UYmouixhazj7tQ== X-Google-Smtp-Source: ALg8bN7AtbD3SD5CGxeQXeObv1giMp5PjVoMZMPETAbMo3HlFVole4EvihbkOE3L1y2UncozKXXISA== X-Received: by 2002:a1c:541a:: with SMTP id i26mr4678660wmb.128.1548375107354; Thu, 24 Jan 2019 16:11:47 -0800 (PST) Received: from cbtest28.netronome.com ([217.38.71.146]) by smtp.gmail.com with ESMTPSA id y138sm71273216wmc.16.2019.01.24.16.11.46 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 24 Jan 2019 16:11:46 -0800 (PST) From: Jiong Wang To: ast@kernel.org, daniel@iogearbox.net Cc: netdev@vger.kernel.org, oss-drivers@netronome.com, Jiong Wang Subject: [PATCH bpf-next v3 02/16] bpf: refactor verifier min/max code for condition jump Date: Thu, 24 Jan 2019 19:10:14 -0500 Message-Id: <1548375028-8308-3-git-send-email-jiong.wang@netronome.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1548375028-8308-1-git-send-email-jiong.wang@netronome.com> References: <1548375028-8308-1-git-send-email-jiong.wang@netronome.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The current min/max code does both signed and unsigned comparisons against the input argument "val" which is "u64" and there is explicit type casting when the comparison is signed. As we will need slightly more complexer type casting when JMP32 introduced, it is better to host the signed type casting. This makes the code more clean with ignorable runtime overhead. Also, code for J*GE/GT/LT/LE and JEQ/JNE are very similar, this patch combine them. The main purpose for this refactor is to make sure the min/max code will still be readable and with minimum code duplication after JMP32 introduced. Reviewed-by: Jakub Kicinski Signed-off-by: Jiong Wang --- kernel/bpf/verifier.c | 172 +++++++++++++++++++++++++++++--------------------- 1 file changed, 99 insertions(+), 73 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 8cfe39e..eae6cb1 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4033,9 +4033,13 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *vstate, */ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) { + s64 sval; + if (__is_pointer_value(false, reg)) return -1; + sval = (s64)val; + switch (opcode) { case BPF_JEQ: if (tnum_is_const(reg->var_off)) @@ -4058,9 +4062,9 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) return 0; break; case BPF_JSGT: - if (reg->smin_value > (s64)val) + if (reg->smin_value > sval) return 1; - else if (reg->smax_value < (s64)val) + else if (reg->smax_value < sval) return 0; break; case BPF_JLT: @@ -4070,9 +4074,9 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) return 0; break; case BPF_JSLT: - if (reg->smax_value < (s64)val) + if (reg->smax_value < sval) return 1; - else if (reg->smin_value >= (s64)val) + else if (reg->smin_value >= sval) return 0; break; case BPF_JGE: @@ -4082,9 +4086,9 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) return 0; break; case BPF_JSGE: - if (reg->smin_value >= (s64)val) + if (reg->smin_value >= sval) return 1; - else if (reg->smax_value < (s64)val) + else if (reg->smax_value < sval) return 0; break; case BPF_JLE: @@ -4094,9 +4098,9 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) return 0; break; case BPF_JSLE: - if (reg->smax_value <= (s64)val) + if (reg->smax_value <= sval) return 1; - else if (reg->smin_value > (s64)val) + else if (reg->smin_value > sval) return 0; break; } @@ -4113,6 +4117,8 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, struct bpf_reg_state *false_reg, u64 val, u8 opcode) { + s64 sval; + /* If the dst_reg is a pointer, we can't learn anything about its * variable offset from the compare (unless src_reg were a pointer into * the same object, but we don't bother with that. @@ -4122,19 +4128,22 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, if (__is_pointer_value(false, false_reg)) return; + sval = (s64)val; + switch (opcode) { case BPF_JEQ: - /* If this is false then we know nothing Jon Snow, but if it is - * true then we know for sure. - */ - __mark_reg_known(true_reg, val); - break; case BPF_JNE: - /* If this is true we know nothing Jon Snow, but if it is false - * we know the value for sure; + { + struct bpf_reg_state *reg = + opcode == BPF_JEQ ? true_reg : false_reg; + + /* For BPF_JEQ, if this is false we know nothing Jon Snow, but + * if it is true we know the value for sure. Likewise for + * BPF_JNE. */ - __mark_reg_known(false_reg, val); + __mark_reg_known(reg, val); break; + } case BPF_JSET: false_reg->var_off = tnum_and(false_reg->var_off, tnum_const(~val)); @@ -4142,38 +4151,46 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, true_reg->var_off = tnum_or(true_reg->var_off, tnum_const(val)); break; - case BPF_JGT: - false_reg->umax_value = min(false_reg->umax_value, val); - true_reg->umin_value = max(true_reg->umin_value, val + 1); - break; - case BPF_JSGT: - false_reg->smax_value = min_t(s64, false_reg->smax_value, val); - true_reg->smin_value = max_t(s64, true_reg->smin_value, val + 1); - break; - case BPF_JLT: - false_reg->umin_value = max(false_reg->umin_value, val); - true_reg->umax_value = min(true_reg->umax_value, val - 1); - break; - case BPF_JSLT: - false_reg->smin_value = max_t(s64, false_reg->smin_value, val); - true_reg->smax_value = min_t(s64, true_reg->smax_value, val - 1); - break; case BPF_JGE: - false_reg->umax_value = min(false_reg->umax_value, val - 1); - true_reg->umin_value = max(true_reg->umin_value, val); + case BPF_JGT: + { + u64 false_umax = opcode == BPF_JGT ? val : val - 1; + u64 true_umin = opcode == BPF_JGT ? val + 1 : val; + + false_reg->umax_value = min(false_reg->umax_value, false_umax); + true_reg->umin_value = max(true_reg->umin_value, true_umin); break; + } case BPF_JSGE: - false_reg->smax_value = min_t(s64, false_reg->smax_value, val - 1); - true_reg->smin_value = max_t(s64, true_reg->smin_value, val); + case BPF_JSGT: + { + s64 false_smax = opcode == BPF_JSGT ? sval : sval - 1; + s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval; + + false_reg->smax_value = min(false_reg->smax_value, false_smax); + true_reg->smin_value = max(true_reg->smin_value, true_smin); break; + } case BPF_JLE: - false_reg->umin_value = max(false_reg->umin_value, val + 1); - true_reg->umax_value = min(true_reg->umax_value, val); + case BPF_JLT: + { + u64 false_umin = opcode == BPF_JLT ? val : val + 1; + u64 true_umax = opcode == BPF_JLT ? val - 1 : val; + + false_reg->umin_value = max(false_reg->umin_value, false_umin); + true_reg->umax_value = min(true_reg->umax_value, true_umax); break; + } case BPF_JSLE: - false_reg->smin_value = max_t(s64, false_reg->smin_value, val + 1); - true_reg->smax_value = min_t(s64, true_reg->smax_value, val); + case BPF_JSLT: + { + s64 false_smin = opcode == BPF_JSLT ? sval : sval + 1; + s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval; + + false_reg->smin_value = max(false_reg->smin_value, false_smin); + true_reg->smax_value = min(true_reg->smax_value, true_smax); break; + } default: break; } @@ -4198,22 +4215,23 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, struct bpf_reg_state *false_reg, u64 val, u8 opcode) { + s64 sval; + if (__is_pointer_value(false, false_reg)) return; + sval = (s64)val; + switch (opcode) { case BPF_JEQ: - /* If this is false then we know nothing Jon Snow, but if it is - * true then we know for sure. - */ - __mark_reg_known(true_reg, val); - break; case BPF_JNE: - /* If this is true we know nothing Jon Snow, but if it is false - * we know the value for sure; - */ - __mark_reg_known(false_reg, val); + { + struct bpf_reg_state *reg = + opcode == BPF_JEQ ? true_reg : false_reg; + + __mark_reg_known(reg, val); break; + } case BPF_JSET: false_reg->var_off = tnum_and(false_reg->var_off, tnum_const(~val)); @@ -4221,38 +4239,46 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, true_reg->var_off = tnum_or(true_reg->var_off, tnum_const(val)); break; - case BPF_JGT: - true_reg->umax_value = min(true_reg->umax_value, val - 1); - false_reg->umin_value = max(false_reg->umin_value, val); - break; - case BPF_JSGT: - true_reg->smax_value = min_t(s64, true_reg->smax_value, val - 1); - false_reg->smin_value = max_t(s64, false_reg->smin_value, val); - break; - case BPF_JLT: - true_reg->umin_value = max(true_reg->umin_value, val + 1); - false_reg->umax_value = min(false_reg->umax_value, val); - break; - case BPF_JSLT: - true_reg->smin_value = max_t(s64, true_reg->smin_value, val + 1); - false_reg->smax_value = min_t(s64, false_reg->smax_value, val); - break; case BPF_JGE: - true_reg->umax_value = min(true_reg->umax_value, val); - false_reg->umin_value = max(false_reg->umin_value, val + 1); + case BPF_JGT: + { + u64 false_umin = opcode == BPF_JGT ? val : val + 1; + u64 true_umax = opcode == BPF_JGT ? val - 1 : val; + + false_reg->umin_value = max(false_reg->umin_value, false_umin); + true_reg->umax_value = min(true_reg->umax_value, true_umax); break; + } case BPF_JSGE: - true_reg->smax_value = min_t(s64, true_reg->smax_value, val); - false_reg->smin_value = max_t(s64, false_reg->smin_value, val + 1); + case BPF_JSGT: + { + s64 false_smin = opcode == BPF_JSGT ? sval : sval + 1; + s64 true_smax = opcode == BPF_JSGT ? sval - 1 : sval; + + false_reg->smin_value = max(false_reg->smin_value, false_smin); + true_reg->smax_value = min(true_reg->smax_value, true_smax); break; + } case BPF_JLE: - true_reg->umin_value = max(true_reg->umin_value, val); - false_reg->umax_value = min(false_reg->umax_value, val - 1); + case BPF_JLT: + { + u64 false_umax = opcode == BPF_JLT ? val : val - 1; + u64 true_umin = opcode == BPF_JLT ? val + 1 : val; + + false_reg->umax_value = min(false_reg->umax_value, false_umax); + true_reg->umin_value = max(true_reg->umin_value, true_umin); break; + } case BPF_JSLE: - true_reg->smin_value = max_t(s64, true_reg->smin_value, val); - false_reg->smax_value = min_t(s64, false_reg->smax_value, val - 1); + case BPF_JSLT: + { + s64 false_smax = opcode == BPF_JSLT ? sval : sval - 1; + s64 true_smin = opcode == BPF_JSLT ? sval + 1 : sval; + + false_reg->smax_value = min(false_reg->smax_value, false_smax); + true_reg->smin_value = max(true_reg->smin_value, true_smin); break; + } default: break; }